What came to my mind when reading that was "holy @#$%, one of those two had to be fake - that was either Touma restraining a fake Mikoto, or a fake Touma trying to stop Mikoto". I hope it's the former as there's no way a fake Touma will survive a enraged Mikoto

I doubt either of them are fake considering that Touma has had situations where he needed to shut her up really quickly or stop her from doing something. Though I don't think any of those ever had him covering her mouth and grabbing her like he's about to kidnap or something.